Utilizing the chelating agent, EDTA, in extracting the Wilm's Tumor, we have extracted an antigen from the Wilm's Tumor (nephroblastoma) which has been found to be immunologically cross reactive with fetuin, a bovine fetal serum glycoprotein. Preliminary physicochemical analysis of the antigen indicates that it is of the same approximate molecular weight (ca. 50,000 daltons); has alpha mobility in immunoelectrophoresis runs; has a similar isoelectric point as fetuin. The work as planned is to isolate the antigen on a preparative scale by column isoelectric focusing; adsorption of the EDTA extracts with anti-serum prepared normal human serum and plasma antigens; and by antigen (fetuin) affinity column chromatography. Once the antigen is isolated in "pure form" in sufficient quantity it will be used for detailed physicochemical analysis and used for specific antibody production. Antibodies will be used in RIA assays as well as in other procedures. Development of the radioimmunoassay is in progress as are a series of studies on immunization schedules to produce high avidity antisera. BIBLIOGRAPHIC REFERENCES: John W. Beierle. "On the Isolation and Properties of a Fetuin-like Antigen Associated with Wilm's Tumor In Protides of the Biological Fluids." (ed.) H. Peeters. Pergamon Press, Oxford 1976, pp. 383-390. John W. Beierle, et al. "An Analysis of the Fluid Contents in the Post Anal Sac of the Grey Whale, Esch. Robustus." Bull. So. Cal. Acad Sci 75:(1) 5-10, 1976.